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Dividers & Compasses

Beam Compasses

Mechanical and architectural drawings have sometimes required circles with diameters of several feet instead of the several inches possible with a standard drawing compass. A beam compass was usually sold with just the points, which the user attached to the ends of a metal rod or wooden slat the length of the desired radius of the circle. One end was held in place, and the other end was pivoted around that end, maintaining contact with the paper. The patent model in the collection is a beam compass.

This metal, brass, and ivory U.S. patent model is mounted in a square wooden frame that is painted gold. The trammels are on a 3-1/4" beam that consists of two metal pins and one metal screw. One trammel has a needle point and an ivory handle. The other has an adjustable pen point. Nuts inside the trammels around the screw on the beam set the positions of the trammels. The instrument is supposed to draw lines, circles, concentric circles, and spirals.

Three paper tags are attached to the frame with a red ribbon. The first tag is marked: 1873 (/) M. Toulmin (/) Beam Drafting Compass (/) Received June 5 (/) Passed Aug 5./7. The second tag is marked: 142,823 (/) 3 (/) M. Toulmin (/) Beam Compasses (/) Patented SEP 16 1873 (/) Dividers 1873. A printed picture of the instrument and a summary of the patent application are pasted to the back of this tag. The third tag is marked: (2–225.) (/) No. 142,823. (/) M. Toulmin (/) Beam Compasses (/) Patented Sept. 16th (/) Dividers 1873. This model was found in the Smithsonian, probably during refurbishing of the textile exhibits between 1953 and 1964.

The patentee was probably Joshua Morton S. Toulmin (1823–1896), who was born in Alabama to English immigrants. He was a cotton broker in Mobile in the 1850s and then moved to New Orleans, where he received four patents between 1872 and 1874, including the 1873 patent for this object and "Improvement in Marine Camels" (no. 125,352, issued April 2, 1872). He then became a patent agent in Washington, D.C., and received several more patents himself between 1876 and 1887. He then moved to Baltimore, where he established the short-lived Toulmin Electric Railway Gate Company in 1886 and received more patents between 1887 and 1890, including "Pneumatic Street Car Propulsion" (no. 440,666, issued November 18, 1890). He held a total of about 15 patents for a variety of mechanical and mercantile devices, but this beam compass was apparently never manufactured commercially. Toulmin's son, Harry Aubrey Toulmin (1858–1942), was the highly successful attorney for the Wright Brothers of Dayton, Ohio.

Beam compasses were used to draw circles of large radius by positioning the sliding pieces on a wooden lath. This German silver instrument, also called a draftsman’s trammel, has a smaller sliding piece with a pencil point that may be exchanged for the pen point holder also contained in the case. The smaller sliding piece is engraved with the Kern logo, a K inside a pair of dividers. The larger sliding piece has a needle point. Either end of the needle point may be used.

The larger sliding piece is engraved with a maker’s mark: KERN & Co; AARAUSWISS. No beam, or wooden lath, is included, nor is there room for one in the case. The case is leather over wood, lined with maroon velvet and locked by a button on the side. The top of the case is imprinted with a rectangle that has a fleur-de-lis at each corner. The maker’s mark is stamped in gold: KERN & Co AARAU [/] SWITZERLAND. The owner’s card is inside the case, with “Property [/] of” written in cursive pencil and “L. N. EDWARDS” printed. Carolyn H. Edwards of Glen Echo, Md., bequeathed this beam compass set to the Smithsonian in 1971.

The marks on this compass are similar to those used by Kern between 1885 and 1926. For other instruments manufactured by Kern, see ID numbers MA*247966, 1977.0460.02, 1978.2291.01, and MA*321781.

This instrument consists of a wooden beam and a single German silver trammel with a micrometer and needle point. A large round hole in one end of the beam allows the instrument to be hung. The other end of the beam is marked in pencil at each of the first six inch points. The trammel is similar but not fully identical to Dietzgen's model number 646, which sold with a pair of trammels, two needle/pencil points, and a pen point for $9.20 in 1904–1905. This instrument was owned by the renowned American designer of steam engines, Erasmus Darwin Leavitt Jr. (1836–1916), and donated by his granddaughter, Margaret van D. Rice.

This German silver instrument has steel and brass points. Two trammels have thumbscrews for fastening to a wooden bar (not included) and for attaching one of the five points. One trammel has a micrometer and is marked on the front: KEUFFEL & ESSER Co. N.Y. GERMANY. The back is marked: PARAGON. Above this mark is scratched: CE1RD. Compare this mark to 1978.2110.02.

The attachments include a pencil point, an adjustable pen point, two steel needle points, and one brass needle point. A rectangular wooden case is covered with morocco leather and lined with green velvet. The bottom of the case is marked: GERMANY.

K&E sold this instrument as model number 510 at least as early as 1892, but the Paragon brand was not introduced until 1901. By 1936 the points were stainless steel instead of steel. The price with case was $10.25 in 1909.

This German silver instrument has steel points. The two trammels, or frames for the pencil and needle points, have thumbscrews on their fronts. These thumbscrews are ridged around the edge and have a circular pattern on their tops. The number 19 is engraved inside each trammel. Smaller thumbscrews attach holders for needle and pencil points. These holders have horizontal scrolling but are not identical to each other. Another thumbscrew allows the needle point to be reversed. A micrometer adjustment is below one of the trammels.

A separate adjustable pen point appears to belong to a regular drawing compass, rather than to this beam compass, because it is longer than the other holders and shaped differently. Compare this piece to MA*335338 and MA*335340. No bar for connecting the trammels was received with the instrument.

This beam compass is similar but not identical to Dietzgen model number 1033, which sold for $6.90, and to Keuffel & Esser model 770, which sold for $7.00. These beam compasses are also similar but not identical to each other. Although this beam compass could not be identified, it probably was made in Germany and dates to the first decade of the 20th century, like the advertised instruments.

Leslie Leland Locke (1875–1943) earned bachelor's (1896) and master's (1900) degrees from Grove City College. He taught mathematics at Michigan State College, Adelphi College, and Brooklyn College and its Technical High School. He was interested in the Peruvian quipu. He donated his collection of early calculating machines to the Smithsonian and his early American textbooks to the University of Michigan.

This German silver instrument has two trammels, one with a reversible needle point and micrometer, and one with a holder for a pencil lead. The pencil holder may be replaced with an adjustable pen point. A rectangular wooden case is covered with morocco leather and lined with green silk and green velvet. The top of the case is marked: CE27RD. An indentation in the case indicates a piece is missing, possibly a container of pencil leads. Compare to 1978.2110.03.

The instrument resembles a beam compass sold by Dietzgen in two different grades from at least 1904 to 1934, first as model numbers 646C ($10.70) and 1034C ($6.60) and then as models 927 ($16.75) and 978 ($8.10). The case was lined with silk only in the 1904 catalog description, but the case of pencil leads was not mentioned until 1926. As with many beam compasses, purchasers had to separately buy a wooden bar to connect the trammels, in widths between 5/32" and 3/16" and lengths between 24" and 60".

This German silver instrument has a rectangular bar 43" long with a micrometer adjustment on one end. The bar has two centimeter scales, divided to millimeters, and two inch scales, divided to twentieths of an inch. One centimeter scale and one inch scale are underneath a frame that holds a needle point and is marked with the micrometer scale and with the words: KEUFFEL & ESSER Co (/) NEW YORK (/) Paragon. The other scale is marked from 1 to 101 cm and 40". A second frame (or trammel) may be moved along these scales and has a holder for a pencil point. Pen and needle points in the case may replace the pencil point. A finer needle point mentioned in K&E catalogs is missing from the case. A two-wheeled attachment slides on to the bar to help control the bar's movement.

The rectangular mahogany case has a section for the accessories and three supports, lined with green velvet. K&E introduced the Paragon brand in 1901 for its finest imported and American-made products. In 1909, the company sold model number 506 for $35.00. It discontinued the instrument between 1921 and 1936. The U.S. Naval Observatory transferred this example to the Smithsonian in 1965.

This German silver instrument has steel points. Two rounded tubes (4" and 13" long) may be connected with a collar on the longer tube. A holder for a pricker point is on the shorter tube. It has a cylindrical handle with a crosshatch pattern and a micrometer adjustment that may be moved along a screw extending from the holder. The handle is marked: KEUFFEL & ESSER (/) GERMA[NY].

A second holder may be placed anywhere on the tubes. It may be fitted with an adjustable pen point, a pencil point, or one of two needle points. The needle points fit into a cylindrical ridged handle, but the handle apparently cannot be attached to the tubes. A cylindrical metal case holds two pencil leads.

An oblong black leatherette case is lined with green velvet and marked on the top of the lid: KEUFFEL & ESSER CO. (/) 955. The case is in a dark green paper box with a red and white label: ANVIL BEAM COMPASSES (/) TRADE MARK K & E CO. (/) 1 ONLY 955 C (/) REG. U.S. PAT. OFF. In 1936, K&E sold the instrument and case as part of its Anvil product line for $9.50. (The C in the model number refers to the case.) The description does not mention the handle for the needle points or the tube for the pencil leads, but there are spaces for both items in the case. This instrument was not advertised in the 1927 and 1944 K&E catalogs.

This steel instrument is plated with chromium and stored in a leatherette pocketbook case lined with purple velvet. The inside of the flap is marked: DIETZGEN. The back of the case is marked: GERMANY. The beam compass consists of a solid tubular beam, 13" long and 3/16" in diameter; a second solid tubular beam, 6" long and 3/16" in diameter; a coupling for joining the beams with a thumbscrew; a needle point with a micrometer adjustment; a second needle point; a pencil point; a pen point; and a cylindrical case holding one extra lead and two additional needles. The handles on the points are cylindrical with a honeycomb pattern. The thumbscrew on the needle point with micrometer is marked: DIETZGEN GERMANY.

The Eugene Dietzgen Co., a Chicago manufacturer and retailer of mathematical instruments, advertised the model 967A "Champion" brand beam compass and case in the late 1930s for $8.50. Dietzgen may have purchased instruments in the Champion line from Bayerische Reisszeugfabrik, a company in Nuremberg, Germany, that was owned by Joseph Dietzgen and made ECOBRA brand slide rules. See 1984.1071.04.

This instrument has two very tarnished flat metal bars, each 22 cm long, with tapered ends that interlock to make a beam of 40.9 cm. The two steel sliding trammels resemble pencils and are marked: T.A. & SONS. The longer trammel has a needle point, and the shorter has a pencil point. The shorter trammel has a cam wheel that allows adjustment up to 3/16". Spring tension in both trammels may be adjusted by turning a knurled nut.

John Wesley Oehrli (1903–1969), an engineer and inventor who lived in State College, Pa., applied for a patent on this beam compass in 1944. He moved to Southern California by 1953, where he worked for McCulloch Motors Corporation, and received a total of 11 patents, mainly for chain saws and planetary drives in internal combustion engines. Theodore Alteneder & Sons sold the "improved tubular beam compass" as model number 1666 from 1945 through at least 1952 for $16.50. This object originally would have had a case.